This research proposal has as its major objective the investigation of carbohydrate-binding proteins and their interaction with simple and complex carbohydrates and plant and animal cells. Phytohemagglutinins (lectins) will be isolated from plant seeds and fungi by affinity chromatogrphy. The purified proteins will be characterized as to molecular weight, amino acid and carbohydrate composition, metal content and subunit structure and carbohydrate-binding specificity. Circular dichroism studies, chemical modifications, tryptic peptide mapping and end group analyses will also be carried out. Lectins will be immobilized and used as adsorbents for the isolation of polysaccharides, glycoproteins and glycoplipids. Cell binding studies of lectins to erythrocytes, lymphocytes, and certain malignant cells will be undertaken and attempts will be made to isolate lectin receptor glycoproteins from these cells. Affinity labeling of lectin-active sites will be attempted. Immune antibodies against defined carbohydrates conjugated to carriers will be raised in rabbits. The antibodies will be characterized with respect to specificity and cross reaction with naturally occurring, carbohydrate-containing macromolecules. Attempts will be made to use these antibodies as probes for identifying structural features on cell surfaces.